Incidence Of Reactive Hypertension Research Articles

Comparison Between 3 Different Norepinephrine Bolus Doses for Management of Postspinal Hypotension During the Caesarean Section for Patients with Preeclampsia: A Randomized Controlled Trial

Background: There is no established dose for norepinephrine (NE) in the management of postspinal hypotension. The data on its use in women with preeclampsia (PE) are limited. Objectives: This study aimed to compare the effect of using different NE bolus doses for the management of postspinal hypotension during lower segment cesarean section for patients with PE. Methods: This randomized, double-blind trial included mothers with PE scheduled for cesarean delivery who developed postspinal hypotension. Sixty participants were allocated to receive 3, 4, or 5 µg of NE bolus. The primary outcome was the neonatal bicarbonate level. The secondary outcomes were successful management of hypotension, incidence of reactive hypertension, nausea, vomiting, systolic blood pressure (SBP), and heart rate (HR) readings through the operation, umbilical blood gases, and Apgar scores. Results: The number of hypotensive episodes, bradycardia episodes, successfully treated hypotensive episodes, and total NE dose per patient were lower in the 4- and 5-µg groups compared with the 3-µg group. Systolic blood pressure was generally higher in the 4- and 5-µg groups than in the 3-µg group starting from 12 min postspinal till 28 min postspinal. The heart rate decreased compared to the baseline reading starting from 4, 6, and 2 min postspinal in the 3-, 4-, and 5-µg groups, respectively, till 28 min postspinal. Also, HR was higher in the 4- and 5-µg groups compared to the 3-µg group at 6-12 min postspinal. Following the first NE bolus, SBP remained lower than the baseline reading in the 3 groups, and HR decreased compared to the baseline reading in the 3- and 5-µg groups only. Conclusions: The 3-, 4-, and 5-µg doses had comparable efficacy in managing the first hypotensive episode and comparable neonatal outcomes. The 4- and 5-µg doses significantly decreased the total NE requirements and the number of hypotensive episodes. The incidence of maternal bradycardia was not significantly different between the groups.

A Randomized Double-Blinded Dose-dependent Study of Metaraminol for Preventing Spinal-Induced Hypotension in Caesarean Delivery.

Purpose: Prophylactic infusion of a vasopressor is preferred as a rational choice in clinical practice in Cesarean delivery. Metaraminol is one of most common vasopressors used in obstetric clinical practice. However, the dose-response of metaraminol has not been fully determined and the optimal infusion dose is unknown. Therefore, this study aimed to determine the median effective dose (ED50) and 90% effective dose (ED90) of weight-based fixed-rate metaraminol infusions for preventing spinal-anesthesia-induced hypotension in patients having combined spinal-epidural anesthesia for elective Caesarean delivery. Methods: One hundred and seventeen patients with singleton pregnancies were enrolled and randomly allocated into one of five groups in this study. Patients received prophylactic metaraminol infusion at a fixed rate of 0, 0.25, 1.0, 1.75 or 2.5 μg/kg/min in each group immediately after induction with intrathecal 10 mg of hyperbaric bupivacaine mixed with 5 μg of sufentanil. An effective prophylactic dose was defined as no occurrence of hypotension during the period of spinal introduction and neonatal delivery. Values for ED50 and ED90 of prophylactic infusion of metaraminol were calculated using probit regression. Characteristics of spinal anesthesia and side effects were recorded. Results: The ED50 and ED90 values of weight-based fixed rate of metaraminol infusion were 0.64 (95% CI, 0.04–1.00) μg/kg/min and 2.00 (95% CI, 1.58–2.95) μg/kg/min respectively. The incidence of hypotension decreased with an increased infusion rate of metaraminol in the five groups (test for trend, p < 0.001). The incidence of hypotension was similar between group 0 and 0.25, but significant higher than other groups; the incidence of hypotension was also similar between group 1.0 and 1.75, but higher than group 2.5. The incidence of reactive hypertension was significantly higher in group 2.5 compared to the other groups. Physician interventions were more frequent in group 0, 0.25 and 2.5 than in group 1.0 and 1.75 (adjusted p < 0.001). No difference was found in neonatal outcomes, including Apgar score and pH value of the umbilical artery. Conclusion: In summary, we have compared four different prophylactic weight-based infusion doses of metaraminol for preventing post-spinal hypotension in Cesarean delivery. The ED50 and ED90 values of metaraminol infusion for preventing spinal anesthesia-induced hypotension were 0.64 μg/kg/min and 2.00 μg/kg/min, respectively. This finding may be helpful for guiding clinical practice and further research.

Prevention of hypotension during elective cesarean section with a combination of colloid co-load and a continuous infusion of a vasoconstrictive agent: A comparative randomized study

Background: Spinal anesthesia is considered the anesthetic technique of choice in cesarean section but it can be frequently complicated by hypotension, with occasionally serious consequences for both the mother and fetus. One of the standard techniques used in the prevention of maternal hypotension is the administration of a continuous phenylephrine infusion. However, phenylephrine can lead to baroreceptor-mediated reflex bradycardia with untoward consequences for the maternal cardiac output. Nowadays, noradrenaline has been proposed as an alternative agent in this context, since due to its additional weak dose-dependent β-action, it can be associated with an inferior incidence of maternal bradycardia and thus of propensity to decrease the cardiac output. Colloid co-hydration has also been proven to be an effective technique in the prevention of maternal hypotension. This double-blinded, prospective randomized study aimed to investigate whether the addition of a fixed rate phenylephrine infusion or noradrenaline infusion to a colloid co-hydration regimen results in better maternal hemodynamic status or in a more favorable metabolic profile in the newborn as compared to the administration of colloids alone without any vasoconstrictor during elective cesarean section under combined spinal-epidural anesthesia. Materials and methods: One hundred-twenty parturients were randomized to either phenylephrine 50 μg/min (group P) or noradrenaline 4 μg/min (group N) or placebo (group C). All infusions had been prepared in identical syringes and the infusion rate was 30 mL/h in order to ensure the “blindness” of the study. As soon as the spinal injection started, all groups were administered 10 mL/kg of hydroxyethyl starch (HES) solution simultaneously with the onset of vasoconstrictor infusion. The primary end-point of the study was the incidence of maternal hypotension (SAP <80% of baseline). Additionally, maternal hemodynamics at specific time-points were recorded using non-invasive technology (Edwards Lifesciences ClearSight System) as well as the incidence of reactive hypertension, bradycardia, the requirement for bolus vasoconstrictor administration and the fetal acid-base status, the umbilical venous and arterial blood gases and the newborn Apgar score. Results: The incidence of maternal hypotension was higher in group C than in group P and also higher in group C than in group N (p = 0.024 and 0.073, respectively). The need of bolus administration of vasoconstrictor was higher in group C than in group P and also higher in group C than in group N (p = 0.001 and 0.003, respectively). The incidence of bradycardia was higher in group P than in group N (p = 0.018). The incidence of reactive hypertension was higher in group P than in group N and also higher in group P than in group C (p = 0.029 and 0.005, respectively). The need of modification of the infusion rate was higher in group P than in group N and also higher in group P than in group C (p < 0.001 και p = 0.002, respectively). The fetal pH of the umbilical vein was higher in groups N and P than in group C (p < 0.001), the fetal pO2 of the umbilical vein was higher in group N than in group C (p = 0.023) and fetal blood glucose concentration was higher in group N than in group C (p = 0.025) as well as in group N than group P with no statistical significance. Higher systematic vascular resistance index (SVRI) and higher SAP were observed at specific time-points in group P versus the other two groups. Finally, post-delivery Apgar scores were similar in all groups. Conclusions: The combination of a fixed-rate infusion of noradrenaline with the co-administration of colloid seems to be the most effective in the obstetric management of the parturient during cesarean section under regional anesthesia since it ensures maternal hemodynamic stability and a favorable metabolic profile in the newborn. This regimen seems to be superior to either a combination of colloid co-administration with a fixed rate of phenylephrine or to the administration of colloid alone without any vasoconstrictor agent. The higher concentration of fetal blood glucose in group N might be due to a catecholamine-induced glucose metabolism activation and due to a β-receptor-mediated decrease of insulin release.

Comparison of two Norepinephrine rescue bolus for Management of Post-spinal Hypotension during Cesarean Delivery: a randomized controlled trial

BackgroundData on the best norepinephrine bolus dose for management of hypotension are limited. The aim of this study was to compare the efficacy and safety of two norepinephrine bolus doses in the rescue management of maternal hypotension during cesarean delivery.MethodsThis randomized, controlled trial included mothers scheduled for cesarean delivery with spinal anesthesia with a prophylactic norepinephrine infusion. Following spinal anaesthesia administration, a participant was considered hypotensive if systolic blood pressure was ≤80% compared to the baseline reading. Participants were allocated to receive either 6 mcg or 10 mcg norepinephrine bolus for the management of hypotensive episodes. The hemodynamic response after administration of norepinephrine bolus was recorded. The episode was considered successfully managed if systolic blood pressure returned to within 80% from the baseline reading within 2 min after norepinephrine bolus administration, and did not drop again within 6 min after the norepinephrine bolus. The primary outcome was the incidence of successful management of the first hypotensive episode. Other outcomes included systolic blood pressure, heart rate, incidence of maternal bradycardia, and reactive hypertension.ResultsOne hundred and ten mothers developed hypotensive episodes and received norepinephrine boluses for management. The number of successfully managed first hypotensive episodes was 50/57 (88%) in the 6 mcg-treated episodes and 45/53 (85%) in the 10 mcg-treated episodes (p = 0.78). Systolic blood pressure was comparable after administration of either bolus dose. Heart rate was lower after administration of 10 mcg bolus compared to 6 mcg bolus, without significant bradycardia requiring atropine administration. The incidence of reactive hypertension was comparable between both groups.ConclusionIn mothers undergoing elective cesarean delivery under prophylactic norepinephrine infusion at 0.05 mcg/kg/min, there was no advantage to the use of 10 mcg norepinephrine bolus over 6 mcg norepinephrine bolus for the rescue management of first hypotensive episode. Neither of the 2 bolus doses reached a 100% success rate. The incidences of bradycardia and reactive hypertension were comparable between both norepinephrine doses.Trial registrationAt clinicaltrial.gov registry system on January 4, 2019 Clinical trial identifier: NCT03792906.

Norepinephrine versus phenylephrine infusion for prophylaxis against post-spinal anaesthesia hypotension during elective caesarean delivery: A randomised controlled trial

BackgroundProphylactic vasopressors are fundamental during caesarean delivery under spinal anaesthesia. The aim of this work is to compare the efficacy and safety of phenylephrine and norepinephrine when used in variable infusion rate during caesarean delivery. MethodsA randomised, double-blinded, controlled trial was conducted including mothers scheduled for elective caesarean delivery under spinal anaesthesia. Participants were allocated to two groups norepinephrine group (n = 60), and phenylephrine group (n = 63). Participants received prophylactic vasopressors after spinal block at rate started at 0.05 mcg/kg/min and 0.75 mcg/kg/min respectively. The rate of vasopressor infusion was manually adjusted according to maternal systolic blood pressure. Both groups were compared according to incidence of post-spinal hypotension (the primary outcome), incidence of bradycardia, incidence of reactive hypertension, systolic blood pressure, heart rate, rescue vasopressor consumption, number of physician interventions, and neonatal outcomes. ResultsOne hundred and twenty-three mothers were available for final analysis. Both groups were comparable in the incidence of post-spinal hypotension (32% versus 30%, P = 0.8). The number of physician intervention was lower in norepinephrine group. The incidence of bradycardia and the incidence of reactive hypertension were potentially lower in norepinephrine group without reaching statistical significance, (13% vs. 21%, P = 0.3) and (12% vs. 24%, P = 0.1). Rescue vasopressor consumption, and neonatal outcomes were comparable between both groups. ConclusionWhen given in a manually adjusted infusion, norepinephrine effectively maintained maternal SBP during caesarean delivery under spinal anaesthesia with lower number of physician interventions, and likely less incidence of reactive hypertension and bradycardia compared to phenylephrine.

A Comparison of Intravenous Ephedrine or Phenylephrine, for Prevention of Postspinal Hypotension during Elective Lower Abdominal Surgery: A Randomized, Double-blind Case-control Study.

Background:In this randomized, double-blinded case–control study, we investigated the intravenous effects of ephedrine or phenylephrine on prevention of post–spinal hypotension in elective lower abdominal surgery under spinal anesthesia.Materials and Methods:One hundred and thirty-five patients, American Society of Anesthesiologists physical status I or II candidate for elective lower abdominal surgery under spinal anesthesia were randomized to three groups (45 each). According to their allocated group, patients received either ephedrine 2.5 mg (E group), phenylephrine (P group) 25 mic as vasopressor or the same volume of saline normal as placebo (S group) immediately after the spinal anesthesia. hemodynamic parameters, and complications were recorded.Results:Patients’ demographics were similar in all the groups. The mean systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP and also heart rate were similar over time for groups E and P (P > 0.05). The incidence of reactive hypertension was more in group E than group P and placebo (P < 0.05). The incidence of nausea and vomiting were significantly lower in groups E and P in comparison with placebo (P < 0.05).Conclusion:Although the mean fall of SBP and DBP were significantly less in groups E and P compared with placebo but we did not find significant differences in prophylactic use of ephedrine or phenylephrine for prevention of post–spinal hypotension in elective lower abdominal surgery. Vasopressors infusion have added benefit of lower incidence of nausea and vomiting.

Closed‐loop double‐vasopressor automated system vs manual bolus vasopressor to treat hypotension during spinal anaesthesia for caesarean section: a randomised controlled trial

Hypotension necessitating vasopressor administration occurs commonly during caesarean section under spinal anaesthesia. We developed a novel vasopressor delivery system that automatically administers phenylephrine or ephedrine based on continuous non-invasive arterial pressure monitoring. A phenylephrine bolus of 50 μg was given at 30-s intervals when systolic blood pressure fell < 90% of baseline; an ephedrine bolus of 4 mg was given instead if systolic pressure fell < 90% of baseline together with a heart rate < 60 beats.min(-1). The control group used manual boluses of either phenylephrine 100 μg or ephedrine 8 mg, administered at 1-min intervals based on the same thresholds for systolic pressure and heart rate. This randomised, controlled, double-blinded trial involved 213 healthy women who underwent elective caesarean delivery under spinal anaesthesia using 11 mg hyperbaric bupivacaine with 15 μg fentanyl and 100 μg morphine. The automated vasopressor group had better systolic pressure control, with 37/106 (34.9%) having any beat-to-beat systolic pressure reading < 80% of baseline compared with 63/107 (58.9%) in the control group (p < 0.001). There was no difference in the incidence of reactive hypertension, defined as systolic pressure > 120% of baseline, with 8/106 (7.5%) in the automated vasopressor group vs 14/107 (13.1%) in the control group, or total dose of vasopressors. The automated vasopressor group had lower median absolute performance error of 8.5% vs control of 9.8% (p = 0.013), and reduced incidence of nausea (1/106 (0.9%) vs 11/107 (10.3%), p = 0.005). Neonatal umbilical cord pH, umbilical lactate and Apgar scores were similar. Hence, our system afforded better control of maternal blood pressure and reduced nausea with no increase in reactive hypertension when compared with manual boluses.

A comparison of three vasopressors for tight control of maternal blood pressure during cesarean section under spinal anesthesia: Effect on maternal and fetal outcome

Purpose:Maintaining systolic blood pressure (SBP) at 100% of baseline is best for fetal and maternal outcome. We hypothesized that irrespective of the vasopressor used, maintaining SBP at 100% of baseline with phenylephrine (P), metaraminol (M), or ephedrine (E) will produce the best fetal pH after cesarean section (LSCS) under subarachnoid block (SAB).Materials and Methods:Ninety ASA 1 women scheduled for elective LSCS were randomly allocated to receive P, M, or E. SAB was established with patient in left lateral position using 2.5 cc of 0.5% hyperbaric bupivacaine. Immediately following SAB, patients received a bolus of the study drug (E = 5 mg, M = 0.5 mg, P = 30 mcg) followed by infusion (E = 2.5 mg/min, M = 0.25 mg/min, P = 15 mcg/min) to maintain SBP at 100% baseline. Umbilical blood gases, maternal hemodynamic parameters, and complications were recorded.Results:The umbilical pH was comparable in all the three groups (P > 0.05). The mean SBP from spinal block until delivery was similar over time for all the three groups. The incidence of reactive hypertension was more in group M (P < 0.05) than in group E and group P. Total drug consumption to meet target blood pressure till delivery was 39.3 ± 14.6 mg in group E, 1.7 ± 0.9 mg in group M, and 283.6 ± 99.8 mcg in group P. The incidence of nausea and vomiting was comparable in the three groups.Conclusion:All the three vasopressors were equally effective in maintaining maternal blood pressure as well as umbilical pH during spinal anesthesia for cesarean section without any detrimental effects on fetal and maternal outcome.

The effect of colloid co-hydration on the use of phenylephrine and hemodynamics during low-dose combined spinal-epidural anesthesia for cesarean delivery

Background: Ephedrine has been recommended as the best vasopressor in obstetrics. But, recent clinical evidences show the possibility that phenylephrine has become more pertinent as a primary vasopressor. We think a phenylephrine infusion with colloid co-hydration will be more useful in maintaining baseline blood pressure in combined spinal-epidural anesthesia (CSEA) for cesarean section. Methods: CSEA was performed using 6 mg bupivacaine and 20 μg fentanyl as a spinal and 10 ml of 0.25% levobupivacaine as an epidural in randomized, colloid co-hydration (hydroxyethl starch, HES 500 ml) (group C, n = 34) or no colloid co-hydration (group N, n=34) parturients scheduled to undergo cesarean delivery. After an infusion of 100 μg phenylephrine following the spinal injection, phenylephrine was intermittently infused using a PCA-pump to maintain the baseline blood pressure (BP). Systolic BP and heart rate (HR) were checked and total phenylephrine amount was measured. Nausea and vomiting and fetal umbilical pH/base excess (BE) were also investigated. Results: There was a lower incidence of bradycardia in the C group compared with the N group (5.9% vs. 32.4%, p = 0.014), and total phenylephrine consumption was less in the C group (400 μg vs. 500 μg, p = 0.019). The incidence of reactive hypertension (11.8% vs. 55.9%, p ＜ 0.001), and the hypotension (0% vs. 11.8%, p = 0.114) were lower in the C group, too. The others were comparable in both groups. Conclusions: Colloid co-hydration was effective in reducing the phenylephrine use and the incidences of abnormal hemodynamics such as hypotension, bradycardia and hypertension in low-dose CSEA for cesarean delivery. (Korean J Anesthesiol 2008; 55: 685~90)